Controlling emissions from glycol dehydrators

摘要

Method and apparatus are disclosed which are improvements in the conventional method and apparatus for extracting water from a gas stream such as a natural gas stream by contacting the stream with a glycol to absorb the water, and then regenerating the glycol for further use in extraction by heating the moist glycol in a glycol regenerator to vaporize the water contained in same as steam. The improvement enables control of emissions of volatile organic compounds which have been absorbed by the glycol during contact with the gas stream, while minimizing the contaminants in the water streams produced. The vented steam and gaseous volatile organics are flowed from the glycol regenerator as input to a cooling condenser having successive air and water-cooled condensers, to produce a condenser water stream having a relatively high content of the organic compounds. The condenser water stream is passed to a cooling tower and then through the tower in counter-current or cross-current relation to stripping air, whereby the condenser water stream is stripped of substantial parts of its organics content and emerges as a stripped water stream having low content of the organics. The stripped water stream is used to cool the water-cooled condenser.